The Apache Commons Math project is a library of lightweight, self-contained mathematics and statistics components addressing the most common practical problems not immediately available in the Java programming language or commons-lang.

Apache Hadoop Common

Apache POI - Java API To Access Microsoft Format Files

Spark SQL is Apache Spark's module for working with structured data based on DataFrames.

Core libraries for Apache Spark, a unified analytics engine for large-scale data processing.

The jmh is a Java harness for building, running, and analysing nano/micro/macro benchmarks written in Java and other languages targeting the JVM.

The core Java API for building stream processing applications with Apache Flink.

Core instrumentation library for the simpleclient.

The machine learning library for Apache Spark, providing scalable algorithms and tools for ML pipelines.

Apache Solr (module: solrj)

Confluence Core